[CF-metadata] CF names / inherent optical properties in seawater

[Frederic MELIN]

Dear all,

 

I’d like to discuss names for inherent optical properties in seawater. 

 

The result of bio-optical algorithms applied to ocean color data often
expresses values in terms of absorption ‘a’ and backscattering ‘bb’
coefficients. These in turn are decomposed into several contributions:

 

bb = bb_w + bb_p , backscattering due to pure seawater and particle ,

 

a = a_w+a_phy+a_cdom+a_nap , absorption due to pure seawater, phytoplankton
, chromophoric dissolved organic matter and non-algal particles (or
detritus).

Algorithms often directly output the sum a_cdom + a_nap (they have similar
spectral shapes and are not easily distinguishable).

 

Satellite products now include a_phy, a_cdom+a_nap and bb_p , usually
expressed at a given wavelength in the visible, with units of m^-1 (they are
properties of a unit volume of water) . 

 

In the current list, I noticed:

volume_absorption_coefficient_of_radiative_flux_in_sea_water 

and

volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_dissolve
d_organic_matter

 

as well as 

volume_backwards_scattering_coefficient_of_radiative_flux_in_sea_water .

 

In order to define bb_p, a_phy, and a_cdom+a_nap , should I write ? :

 

-
volume_backwards_scattering_coefficient_of_radiative_flux_in_sea_water_due_t
o_particles 

 

-
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_phytopla
nkton

-
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_dissolve
d_organic_matter_and_non_algal_particles

(it would then make sense to define as well
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_non_alga
l_particles )

 

Finally, should names start with “volume_spectral_...” to state that the
quantities are expressed at a specific wavelength?

 

Thanks for any feedbacks,

Best,

frédéric

 

====================================

Frédéric Mélin

 

E.C. Joint Research Centre

Institute for Environment and Sustainability 

 

T.P. 272 I-21027 Ispra (VA)

 

Tel.: +39.0332.785627

Fax:  +39.0332.789034

E-mail: frederic.melin at jrc.ec.europa.eu

WWW: oceancolour.jrc.ec.europa.eu

====================================

 

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